In integrated circuit manufacturing processes, semiconductor wafers typically need to be processed on spin modules, for example, when photo resists are coated on the semiconductor wafers and developed. During these process steps, the semiconductor wafers need to be centered accurately on the chucks that are used to support and secure the semiconductor wafers.
Semiconductor wafers can be placed on chucks first, and then centered. Alternatively, the placement and the centering can be performed simultaneously by placing wafers on movable arms, which have guide pin sets for defining the accurate positions of the semiconductor wafers. The positions of guide pin sets are accurately adjusted to allow the semiconductor wafers to be placed on them, with a very small allowance, so that the wafers will not shift when limited by the guide pin sets.
The required accuracy in the positions of guide pin sets, however, causes a reduction in the throughput of manufacturing processes when wafers having different sizes are processed on the same spin module. For example, semiconductor wafer and the corresponding carrier wafers have different sizes, and may need to be processed by the same spin module. For the same spin module to handle wafers with different sizes, the positions of the guide pins need to be adjusted back and forth to suit different sizes. The throughput is thus adversely affected.